1. Field of the Invention
The invention relates generally to urinalysis devices.
2. Description of Prior Art and Related Information
Chemical contact test devices generally include a test agent, such as a test pad containing one or more chemicals, adapted to come into contact with a fluid sample to be tested. Specific chemicals are provided in the test agent to react with the certain chemicals being detected in the fluid sample. If the chemicals being tested for are present in the sample, a chemical reaction occurs, resulting in a visible color change in the testing agent. By comparison with a color chart, the resulting color on a pad indicates whether certain chemicals are present. Such chemical xe2x80x9ccontactxe2x80x9d tests include devices which may be used, for example, in urinalysis to aid in diagnosis and monitoring the progress of disease, to screen a population for asymptomatic, congenital or hereditary diseases, and to monitor the effectiveness or complications of therapy. In addition, it may be used to test for chemical adulteration of body fluids, such as urine.
As drug screening becomes increasingly prevalent, a greater need exists to detect adulterants used to thwart such drug tests. Adulterants, such as bleach for example, may interfere with the mechanism of the drug test, causing the test to report false results. A major problem with present drug screening, therefore, is the inaccuracy of a drug test due to the possible usage of adulterants.
Adulteration testing devices have been developed to address this uncertainty. Conventional adulteration testing devices include a dipstick containing several chemical contact test pads which is immersed into the fluid sample being tested. A major problem with conventional adulteration testing is that it consists of an additional test that must be performed with a device that is different and separate from the drug testing device. Hence, technicians are compelled to divide a liquid sample into multiple portions, increasing the probability of mix-ups and messy spills. A further disadvantage of the dipstick, as with other conventional urinalysis tests, is that once the fluid sample contacts the testing agent, chemicals from the testing agent may leach into the fluid sample. Thus, all of the fluid sample within a container is contaminated and rendered obsolete for further testing. If the fluid sample is not initially divided into separate containers, testing for adulteration may render the entire sample obsolete, thus requiring the donor to give a new sample and the technician to repeat testing.
In addition to drug testing and adulteration testing, the same contamination problem exists with current urinalysis in other types of applications, such as in the diagnosis of disease. Once a portion of a fluid sample contacts the testing agent, chemicals from the testing agent leach into that portion making it unusable for any further tests. This often leads to additional expense and inconvenience as the donor must resubmit a sample while additional materials and labor is required for retesting the new sample.
Furthermore, conventional urinalysis test devices include the dipstick which indicate the presence of certain substances, such as glucose or blood. In addition to the contamination problem, a conventional dipstick requires a large volume of urine held in a container of sufficient depth to allow a necessary length of the stick to be immersed. If a particular sample from a donor is small, testing the urine with a conventional urinalysis device may be precluded. Additional time, expense and inconvenience are incurred as the donor is compelled to resubmit a larger sample.
In one aspect, a lateral flow test strip assembly is provided for testing a liquid sample. The assembly comprises a support, a contact detection pad coupled to the support, and a reagent-free absorbent strip coupled to the support. As used in the specification and recited in the claims, the contact detection pad comprises an absorbent carrier and a reagent composition adapted to detect one or more substances which may be found in the liquid sample. Furthermore, as a xe2x80x9ccontactxe2x80x9d detection pad, the reagent composition impregnated therein is adapted to detect such chemicals upon contact, as opposed to antibody-antigen binding associated with immunoassay strips. Thus, the reagent composition in the contact detection pad is not intended to be transported from one region of the pad to another region where a binding compound is disposed. The contact detection pad, therefore, excludes immunoassays, but comprises all other reagent compositions.
In a preferred embodiment, the contact detection pad comprises a contact urinalysis pad to detect one or more substances which may be found in urine. The contact urinalysis pad may comprise an adulteration pad to indicate whether a urine sample has been adulterated. The contact urinalysis pad may further comprise a bodily substance detection pad to detect bodily substances.
The reagent-free absorbent strip is in fluid communication with the contact urinalysis pad and is adapted to receive the urine and to communicate the urine to the contact urinalysis pad. As distinguished from immunoassays, the absorbent strip does not contain any antigens, antibodies, or any other reagents for that matter. Thus, the xe2x80x9creagent-freexe2x80x9d absorbent strip primarily serves to direct the urine sample from a front, receiving portion to a rear end portion, where the urine is then communicated to the contact urinalysis pad.
The assembly further comprises means for preventing the urine from traveling beyond the contact urinalysis pad. The preventing means preferably comprises a liquid impervious pad coupled to the support. The liquid impervious pad is disposed adjacent to the contact urinalysis pad at the opposite end from the absorbent strip. The preventing means further comprises a gap between the contact urinalysis pad and the liquid impervious pad.
In a preferred embodiment, the absorbent strip is in fluid communication with the contact urinalysis pad. More particularly, the absorbent strip directly contacts and overlaps a portion of the contact urinalysis pad. The contact urinalysis pad may comprise an adulteration pad. The contact urinalysis pad may also comprise a bodily substance detection pad that detects for bodily substances other than antigens or antibodies.
In another aspect, a chemical test system is provided and adapted to test for the presence of multiple chemicals in a liquid sample. This multi-test system comprises a first sub-assembly and a second sub-assembly. The first sub-assembly, or base assembly, comprises a first backing, a first contact detection pad coupled to the first backing, and a first absorbent strip coupled to the first backing. The first contact detection pad includes an absorbent carrier and a reagent composition adapted to chemically react with a first chemical. The first absorbent strip is in communication with the first contact detection pad. The second sub-assembly, or add-on assembly, comprises a second absorbent strip in communication with the first absorbent strip, a second contact detection pad in communication with the second absorbent strip, and a second backing disposed between the second contact detection pad and the first absorbent strip.
The multi-test system further comprises a first liquid impervious pad coupled to the first backing and disposed adjacent to the first contact detection pad opposite to the first absorbent strip. The first liquid impervious pad is spaced apart from the first contact detection pad. The multi-test assembly further comprises a second liquid impervious pad coupled to the second backing and disposed adjacent to the second contact detection pad opposite to the second absorbent strip. The second liquid impervious pad is spaced apart from the second contact detection pad.
In a preferred embodiment, at least a portion of the first contact detection pad and at least a portion of the second contact detection are exposed. The first contact detection pad preferably comprises a first urinalysis pad. The second contact detection pad preferably comprises a second urinalysis pad.
In a further aspect, a chemical testing device is provided. The device comprises a housing, a contact urinalysis pad including a reagent composition adapted to react with one or more specific chemicals upon contact, and an absorbent strip in communication with the contact urinalysis pad. The housing includes means for viewing at least a portion of the contact urinalysis pad. In a preferred embodiment, the housing comprises a cassette. The housing comprises an aperture open to at least a portion of the absorbent strip. The device further comprises a lateral flow immunoassay strip disposed substantially within the housing.
In another preferred embodiment, the housing comprises a lid adapted to be removably coupled to a vessel. The device further comprises means for introducing a liquid sample in the vessel to the absorbent strip. The contact urinalysis pad preferably comprises an adulteration pad or a bodily substance detection pad. The device further comprises a lateral flow immunoassay strip disposed substantially within the housing.
A method for performing urinalysis is also provided. The method comprises receiving the liquid sample with a reagent-free absorbent strip, providing an urinalysis pad with a composition dispersed therein and adapted to test for a target substance upon contact, laterally flowing the liquid sample to the urinalysis pad with the reagent-free absorbent strip, and providing a detectable response as a result of detection of the target substance. The method further comprises assaying for a immunological chemical with a lateral flow immunoassay strip and preventing the liquid sample from traveling beyond the urinalysis pad.
A method for manufacturing a combined drug testing and adulteration testing device is provided as well. The method comprises providing a housing, disposing a drug test strip in the housing, disposing in the housing a reagent-free absorbent strip in communication with a contact detection pad, and preventing fluid communication between the drug test strip, on the one hand, and the absorbent strip and the contact detection pad, on the other hand. The method further comprises providing a stop to prevent a sample liquid absorbed in the contact detection pad from traveling beyond the contact detection pad. Providing a housing comprises forming apertures open to the drug test strip and the absorbent strip.
In conclusion, a test strip assembly for detecting the presence of a substance in liquid sample comprises a contact detection pad in communication with a reagent-free absorbent strip. The absorbent strip receives the liquid sample and communicates it to the contact detection pad via lateral flow. The absorbent strip and contact detection pad are adhered to a support. A liquid impermeable pad is disposed adjacent to and spaced apart from the contact detection pad to prevent any further travel of the sample. Further add-on assemblies may be coupled to the base test strip assembly. The test strip assembly may be disposed in a housing along with a drug test strip to form a device that performs multiple types of tests. Methods for assaying and manufacturing are also provided.
The invention, now having been briefly summarized, may be better visualized by turning to the following drawings wherein like elements are referenced by like numerals.